Cleaning notches and passages for a feeding or refining element

ABSTRACT

A flinger or refiner plate for a mechanical refiner including deep notches or holes in feeder bars of the flinger plate and/or open passages or holes in bars of the refiner plate. The open passages and/or holes in the bars significantly reduce stagnate flow zones at the trailing side of the bars during operation of the mechanical refiner. The reduction of the stagnate flow zones may reduce or eliminate fiber accumulation at the trailing side of the bars.

RELATED APPLICATION

This application claims priority to U.S. Provisional Patent Application62/635,143 filed Feb. 26, 2018, which is incorporated by reference inits entirety.

TECHNICAL FIELD

The invention relates generally to mechanical refiners and moreparticularly to flinger and refiner plates in such refiners, especiallyfor pulping medium density fiberboard production and in mechanicalpulping systems.

BACKGROUND

Mechanical refiners convert into pulp wood chips, recycled paper,recycled corrugated packaging material and other lignocellulosicmaterials (collectively referred to as “feed material”). The mechanicalrefiner applies pressure pulses, shearing forces and other mechanicalforces to separate the feed material into separated fibers that formpulp. The feed material may have a high consistency, such as over 30%dry contents. High consistency cellulosic feed material may be refinedto form medium density fiberboard (MDF) or mechanical pulps such asThermo-Mechanical Pulp (TMP), Chemi-Thermo-Mechanical Pulp (CTMP) andother variations of pulp.

As the feed material flows through the refiner, fibers and extractives,such as resin, sap, pitch and other liquid or liquefied wood componentsin the feed material, tend to accumulate at certain locations in therefiner. These locations include the trailing side of feeder bars onflinger plates and the trailing side of dams between bars in refinerplates.

The accumulations of fiber and extractives become dark, e.g., black, andhard. Occasionally, the accumulations dislodge from the flinger andrefiner plates, and enter the flow of feed materials moving through therefiner. The dislodged accumulations may break into small particles andmix into the flow of feed material. The particles of accumulations formdark specs in the pulp material output from the refiner and in the finalproduct, being paper or board. Pulp material with dark specs reduces thefinal product's desirability and sales value. Accordingly, there is along felt need to reduce dark specs in the pulp material produced bymechanical refiners.

SUMMARY

The inventors believe that the accumulations form due to low pressureregions next to trailing surfaces on the flinger and refiner plates. Thelow pressures are believed to cause stagnate flow of the feed materialin what otherwise is a fast flow of materials through the refiner.Stagnate flow has low kinetic energy and thus low total pressure, ascompared to the total pressure of fast flowing materials. Due to its lowpressure, stagnate flow traps material that would otherwise flow throughthe refiner. The trapped material adheres to surfaces on the flinger andrefiner plates adjacent the stagnate flow. These surfaces tend to betrailing surfaces of the bars of flinger plates, and trailing surfacesnear or on dams in grooves of a refiner plate. The material remainstrapped against the trailing surfaces and is blackened by the heat inthe refiner.

The inventors conceived of a solution to the accumulations by increasingthe pressures in stagnate flow regions. The pressure can be increased bycreating notches and/or holes in the bars of a flinger plate and holesin the bars of a refiner plate. The notches and holes extend from aleading edge of a bar to a trailing edge of the bar. The notches andholes create a passage through the bar between a high pressure region atthe leading side of a bar and a low pressure region at a trailing sideof a bar.

The holes in the bars of a refiner plate open on a trailing side of thebar just behind a dam connected to the bar. Pressurized fluid, such assteam, flows through the holes to increase the pressure of the stagnantflow. The increased pressure should add energy to the stagnate flowregions and thereby reduce the tendency of fibers and other materials toaccumulate behind dams and on the trailing sides of feeder bars.

The new designs of notches or holes in the bar of a flinger plate andholes in the bars of a refiner plate should reduce the low pressure thatusually exists on the trailing side of feeder bars and downstream ofdams in grooves between refining bars. The reduction in pressuredifferential may reduce or eliminate the fiber accumulations that occurin conventional flinger and plate designs by reducing or eliminatingstagnate pressure zones.

An exemplary flinger plate or refiner plate in accordance with thepresent disclosure comprises deep notches or holes in the bars of theplate. The notches or holes in the bars allow steam to flow from thehigh pressure leading side of the bar to the low pressure trailing sideof the bar.

The notches or holes in or through a bar of a flinger or refiner platemay be oriented to reduce the fiber entrained with the steam flowingthrough the notches or holes. To reduce the fibers in the steam flowingthrough the bars, the notches or holes may be aligned perpendicularly tothe bars, or at an acute or obtuse angle to the bars.

An exemplary flinger plate for a mechanical refiner may comprise: afront face, a back face, a substrate separating the front face from theback face, a center hub extending from the front face, feeder barsextending from the front face, wherein the feeder bars extend radiallyoutward along the front face from the center, a deep notch or holedisposed in a feeder bar of the feeder bars. The deep notch or holeextends through the bar and is configured to allow fluid to flow throughthe bar. The deep notch or hole may be oriented to reduce the likelihoodthat fiber will travel through the deep notch when the flinger plate isused in a mechanical refiner.

The notch may have an opening at a leading side of the feeder bar orrefiner bar that has a cross-sectional area which is smaller than across-sectional area of an outlet of the notch at the trailing side ofthe bar. Similarly, the cross-sectional area of the notch may graduallyincrease from the inlet to the outlet of the notch. Similarly, hole(s)in each bar may have an opening at a leading side of the bar that has across-sectional area smaller than a cross-sectional area of an outlet ofthe hole at the trailing side of the bar. The cross-sectional area ofthe hole may gradually increase from the inlet to the outlet of thehole. The holes may be an alternative to the notches or used in additionto the notches. For example, notches may be in bars on a flinger plateand holes may be bars on a refiner plate in the same refiner.

A mechanical refiner plate segment has been conceived and is disclosedherein which includes: a substrate having a radially inward edge and aradially outward edge; a refining surface including bars separated bygrooves, wherein the bars and grooves extend towards the radiallyoutward edge; dams in the grooves, wherein the dams in each groove spanbetween the adjacent bars on opposite sides of the groove; and at leastone open passage extending through one of the adjacent bars, wherein theopen passage has one end adjacent or near a trailing side of one of thedams in the groove.

The mechanical refiner plate segment may have an open passage with across sectional area of at least nine (9) mm² for an entirety of alength of the open passage. The open passage may be below a ridge of theone of the adjacent bars by at least 10%, or 15%, or 25% of the heightof the one of the adjacent bars. The open passage may have an inlet at aleading side of the refiner bar that has a cross-sectional area smallerthan a cross-sectional area of an outlet of the passage at the trailingside of the bar. Similarly, the cross-sectional area of the open passagemay gradually increase from the inlet to the outlet. Also, there may bean open passage associated with each of the dams in the refiner platesegment.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following more particulardescription of exemplary embodiments of the disclosure, as illustratedin the accompanying drawings. The drawings are not necessarily to scale,with emphasis instead being placed upon illustrating the disclosedembodiments.

FIG. 1 is a cross sectional schematic drawing of a portion of amechanical refiner machine for pulping cellulosic feed material.

FIG. 2 shows a front face of a flinger plate.

FIG. 3 is a cross-sectional view of the flinger plate shown in FIG. 2taken along the line 3-3 in FIG. 1.

FIG. 4 is a front view of a refiner plate segment.

FIG. 5 is side view of a portion of a cross section of the refiner platesegment shown in FIG. 4.

DETAILED DESCRIPTION

FIG. 1 shows in cross section a conventional single-disc refiner 10having a housing 12 defining an internal chamber 14. A rotor discassembly 16 in the chamber is turned by a shaft 18 driven by a motor.The rotor disc assembly includes a supporting disc 20, a circularflinger plate 22 attached to a front face of the supporting disc 20, andan annular assembly of pie-shaped refiner plate segments 24 mounted tothe front face of the supporting disc 20. Inner edges of the refinerplate segments are adjacent an outer periphery of the flinger plate 22.

A similar annular array of plate segments 26 is arranged on a supportingdisc 28 of a stator disc assembly which is fixed to housing.Alternatively, an annular refiner plate may be used instead of anannular array of plate segments. Further, the refiner plates or platesegments may be arranged in a disc generally conforming to a plane for adisc refiner or as a frustoconical plate or a frustoconical assembly ofplate segment for a conical refiner.

The flinger plate 22 rotates with the rotor disc assembly 16. Theflinger plate accepts feed material from a cellulosic material feedingscrew (not show). Feed material flows from the material feed screw,through at center inlet 30 to the refiner along a flow direction (F)parallel to an axis 32 of rotation of the rotor disc 16. The flingerplate 22 assists in turning the flow of the cellulosic material from anaxial direction 32 to a radial direction that leads a gap 34 between therotor disc assembly and the stator disc assembly. If the refiner disc isconical, the flinger plate assists in turning the flow to a conical paththat leads to a conical gap between conical refiner plates.

As the feed material moves through the gap 34, the material is refinedby bars and grooves on the opposing plate segments 24, 26 of the rotorand stator plate assemblies. The action of the bars and groovesseparates the feed material into fibers and thus into pulp. The pulpflows out of the outer periphery of the gap 34 and into the chamber 14of the housing 12.

FIG. 2 is a front view of a flinger plate 100 for a mechanical refinercomprising feeder bars and deep notches 118, 124 disposed within thefeeder bars. The deep notches may be oriented to reduce the likelihoodthat fiber will travel into and across the notch. FIG. 3 is a side viewof a cross section of the flinger plate 100.

The flinger plate 100 includes a substrate 102 having a front face 104and a back face 105 on an opposite side of the substrate. The flingerplate 100 has a center axis (C) and a center hub 106 centered on theaxis. The center hub may protrude from the front face 104 of thesubstrate and has a planar (flat) face. Alternatively, the center hub106 may be planar with the front face 104 of the substrate or recessedwith respect to the front face of the substrate.

An outer annular periphery 108 of the flinger plate 100 defines theouter edge of the substrate 102. The flinger plate 100 may be a singlecircular disc or an assembly of pie-shaped plate segments that togetherform a circular disc.

Feeder bars 110 protrude from the front face 104 and extend from thecenter hub 105 to the outer periphery 107. The feeder bars 110 are sweptback from a radial line in a rotational direction R. The back sweep ofthe feeder bars 110 aids in flinging feed material radially outward. Theflinger plate 100 and rotor disc assembly rotate in direction R. Thebars can also be straight, either angled in a feeding angle, or arrangedin a substantially radial direction. The flinger plate 100 is secured tothe rotor disc 16 by fasteners (not shown) that extend through fastenerholes 120 in the substrate 102.

The feeder bars 110 each have a leading side 112, a trailing side 114and a wide ridge 116 spanning between top edges of the leading andtrailing sides. Notches 118 extend through feeder bars 110 to formgrooves extending from the ridge 116 down towards and possibly to thesubstrate 104. Each feeder bar may have one, two, three or more notches118 and/or holes 119. The inlet 122 to each of the notches or holes ison the leading side 112 of the feeder bar 110 and the outlet 124 is onthe trailing side 114 of the feeder bar. A radially inward notch 118 orhole 119 on each feeder bar may have an outlet 124 adjacent the centerhub 106.

The notches or grooves may be grouped along the first half or two-thirdsof the radial length of a feeder bar. The depth of the notches may befrom the ridge 116 down half way of the bar to the substrate, two-thirdsto the substrate or all the way to the substrate 104. The notch mayextend into the substrate. Similarly, the holes 119 may extend into thesubstrate.

The notches or holes may be arranged such the inlet 122 is at a shorterradial distance from the center (C) than the outlet 124. The notches orholes may also be perpendicular to the bars, or have a reverseddirection wherein the inlet is at a greater radial distance than theoutlet.

The cross-sectional area of the inlet 122 to a notch 118 or hole 119 maybe smaller than the cross-sectional area of the outlet 124. Similarly,the cross sectional area of a notch or hole may gradually, e.g.,linearly, increase in area from the inlet 122 to the outlet 124.

The notches 118 and holes 119 allow fluid, such as steam, under pressureat a leading side 112 of the feeder bar to pass through the bar to thetrailing side 114. The pressure at the leading side 112 of a feeder bar110 tends to be greater than the pressure at the trailing side 114 dueto the movement of the leading side into the feed material and themovement of the trailing side away from the feed material.

The greater pressure at the inlets 122 of the notches or holes willcause fluids, such as steam, to move through the notches and to thetrailing side 114 of the feeder bars. As the fluid exits the notches,the relatively higher pressure of the fluid increases the pressure atthe trailing side 114 of the feeder bars. This increased pressure at thetrailing sides 114 reduces the tendency of stagnate flow forming inrelatively low regions adjacent the trailing sides 114 of the feederbar.

The notches 118 or holes 119 may be shaped to suppress fibers beingdrawn into the inlets 122 of the notches. The shape of the inlets 122may include an obtuse angle, a curvature along the length of the notchesor a hole, and an acute angle 128 at the outlet 124. The obtuse angle126 may be in a range of 100 degrees to 160 degrees, 115 to 145 degrees,or some other degree. The obtuse angle may be measured at the radiallyinward edge 130 of the inlet 122. The obtuse angle causes flow moving infront of the leading side 112 of the feeder bar 110 to turn greater than90 degrees to enter the inlet 122. The flow that makes this turn shouldbe primarily liquids and not the fibers in the flow. The obtuse angle126 at the inlet 122 also results in a blunt edge at the radiallyoutward side of the inlet. The blunt edge reduces the risk that fibersimpacting the edge are cut or otherwise damaged.

At the outlet 124, the acute angle 128 may be measured at the radiallyinward 132 edge of the outlet 124. The acute angle 128 may be in a rangeof 90 to 30 degrees, 75 to 45 degrees or in another range of degrees.The curvature along the length of the notches 118 or hole 119 provides asmooth transition between the angles of the inlet and outlet to thenotch. The angles of the channels are may be selected to preventpreventing feed material moving across bars and thus create a loss inthe feeding performance. On the other hand, notches or holes that runperpendicular to the bars, or even in a direction towards the outerperiphery of the flinger plate may be desirable in certain cases.

The sidewalls of the notches 118 or holes 119 may be planer andperpendicular to the substrate 102 or angled such that the notch opensfrom the substrate to the ridge 116. The sidewalls may also be curved,such as concave or convex, from the substrate to the ridge.

The holes may be 119 similar to the notches 118, except that the ridgeextends over the holes but not over notches. The holes may be individualholes 119 through a feeder bar, two or more holes that join at theirinlet or outlets, and the holes may be tapered such that theircross-sectional area increases from inlet to outlet. The holes functionsimilarly to the notches to provide pressure equalization across theleading and trailing sides of a bar in a flinger plate.

The notches 118 or holes 119 may each have a cross sectional area of atleast 9 mm² and may have a width less than the width of the feeder barwith the notch (or holes). The width of the notch or hole is from oneside of the notch or hole to an opposite side. The width may be constantalong the length of the notch or hole, except at the inlet and outletsmay expand. The notches or holes may also have a variable width, such asbeing narrow on the leading edge of the bars, and extending towards thetrailing edge of the bars. This prevents large particles of the feedmaterial to enter the notches or holes, but also reduces the risk ofblocking the inlets s with material.

The flinger plate 100 may be formed by casting metal into a mold form ofsand. An imprint of the flinger plate is formed in sand molds which areclamped together to form a cavity that is substantially the same shapeas the flinger plate. Metal is poured in the cavity of the sand mold toform the flinger plate. The flinger plate can also be cast without thenotches, and notches can be made through machining of the bars withsuitable tools. The flinger plate can also be a manufactured plate madeof individually welded components. Holes can be drilled, cast usingcores in the pattern, or made with 3D printed sand molds. Holes can alsobe made in bars prior to making a welded assembly.

FIG. 4 is a front view of a refiner plate segment 200, and FIG. 5 isside view of a portion of a cross section of the refiner plate segment200. The refiner plate segment 200 may be conventional except for theholes in the bars described below.

The refiner plate segment 200 is pie-shaped and is assembled with otherrefiner plate segments on a rotor or stator disc. The refiner platesegments are attached to the disc by fasteners inserted in fastenerholes 202. The refiner plate segments are arranged side 204 to side toform an annular assembly of segments on the disc. The outer edge 206 ofthe refiner plate segment 200 forms a circular perimeter when the platesegments are arranged in the annular assembly. The outer edge 206 of therefining surface of the refiner plate segment. The inner edge 208 of therefiner plate segment 200 may be located on the rotor or stator discadjacent an outer edge of the flinger plate. The inner edges 208 of theassembly of refiner plate segments 200 form a circle that surrounds theouter edge of the flinger plate.

The front face of the refiner plate segment 200 is a refining surface.The front face includes a substrate 210 that extends between the innerand outer edges 206, 208, and between the sides 204 of the refiner platesegment. The substrate may be planar from a disc refiner, or thesubstrate may be arched for a conical refiner.

Extending outward from the substrate 210 are bars 212, 214 and 216arranged in groups. The radially inward most group of bars 212 are thickand spaced relatively far apart. The next group of bars 214 are narrowerand relatively close together, and radially outermost bars 216 are thenarrowest and most closely spaced together. The bars in each group maybe substantially parallel. Between adjacent bars are grooves that extenddown to the substrate 210 and up to the top (ridge) of the bars. Thebars and grooves in each group define a refining sections of the refinerplate segment. The arrangements of groups of bars and grooves shown inFIG. 4 is exemplary. Other refiner plates may have a single group ofbars and grooves, two or more groups or bars and grooves that vary inshape and dimensions in a radial direction of the refiner plate.

The feed material flows radially outward through a gap 34 (FIG. 1)between the front faces of opposing refiner plates or assembly of platesegments. The opposing refiner plates or assembly of plate segments maybe a refiner plate assembly and a stator plate assembly. Some refinersmay have two oppositely rotating discs on either side of the gap. Thebars and grooves of one plate assembly face the bars and grooves on theopposing plate assembly. The bars and grooves refine the lignocellulosicmatter in the feed material by applying pressure pulses and by shearingthe matter.

The grooves 217 between bars 212 in the inner refining zone, the grooves218 between bars 214 in the middle refining zone and the grooves 220between bars 216 is the outer refining zone provide passages for steamand liquids to flow radially outward. While fibers also may flow throughthe grooves, the fibers are refined by flowing over the bars and in thegap between the refiner plates.

To move the fibers out of the grooves and to slow the flow through thegrooves, dams 222, 224, 226, 228 fully or partially block the grooves.Specifically, partial-height dams 222 and full height dams 224 areplaced are at various locations in the grooves between the bars 214.Similarly, partial height dams 228 and full height dams 226 are atvarious locations between the bars 216.

As shown in FIG. 5, partial-height dams 222, 228 extend from thesubstrate 210 towards the ridge 230 of the bars, but do not reach thebars. Full height dams 224, 226 extend from the substrate to the ridgeof the bars. The dams divert material flowing through the groovestowards the gap between the opposing refiner plate assemblies. The damsalso slow the flow of material through the grooves.

The dams create stagnate flow zones 232 in the grooves immediatelydownstream (radially outward) of the dams. Stagnate flow zones collectfibers and other particles due to the low pressures in the zones. Thesefibers and particles can adhere to the back of the dams and the sides ofthe bars near the dams. The accumulations of fibers, pitch and otherparticles tend to become hard and blacken due the high temperatures inthe refiner. The accumulations may periodically break off into smallblack particles that can contaminate and discolor the pulp (separatedfibers) being produced by the refiner. The accumulations also may fillthe grooves and thereby reduce the ability of the refiner plates torefine material and reduce the feed material capacity of the refiner.Thus, the accumulations may require replacement of the refiner platesegments.

To reduce the accumulations behind dams, open passages 234 are formed inthe bars and are each positioned radially outward of a dam. The openpassages 234 allow fluid to flow from a high pressure in a region of onegroove away from a dam through a bar and into a stagnate zone toincrease the pressure in that zone. The increased pressure reduces thetendency for accumulations to form and thereby reduces the risk thatparticles of accumulations will break off and contaminate the pulp.There may be an open passage 234 associated with each dam such that theoutlet of the passage 234 is immediately downstream (radially outwardand adjacent the trailing side) of the dam and the inlet opens to aportion of a groove that does not have a dam. The downstream directionof the feed material is shown by arrow 236 in FIG. 5.

The open passages 234 are below the ridge 230 of the bar. The ridge ofthe bar applies shear and pressure pulses to the feed material. Acontinuously ridge over the open passages 234 allows the ridge tocontinue applying shear and pressure forces. Adding a notch to the ridgeto provide a passage through the bar would interrupt the ridge andreduce the ability of the bar to refine the feed material.

The open passage 234 may extend down to the substrate 210 as shown inFIG. 5 or may in a mid-section of a bar and not reach the substrate. Theopen passage may extend towards the ridge of the bar but should notinterrupt the ridge. There may be a substantial portion of the groove,such as a quarter of the grooves height, between the ridge and the openpassage. Leaving a substantial portion between the ridge and openpassage will allow the ridge to erode without eroding into the openpassage. The open passage may also be partially or fully below (inside)the substrate.

The open passage 234 may have a cross section that is square,rectangular, circular, oval, or any shape that allows steam or otherfluids/material to flow from one groove into the next groove. The crosssectional area of the open passage may be 9 mm² or at least grater than7 to 8 mm². For example, an open passage 234 may have a square cross of3 mm×3 mm. The open passages 234 should not be too small, such as below7 mm² to avoid plugging of the passage with material. Similarly, theopen passages 234 should not be so large as to weaken the ridge or thebar. Open passages 234 having a dimension of 3 mm to 5 mm in a directionfrom the substrate to the ridge may be advantageous in provide a largeopening and not weakening the ridge.

Moreover, the passages 234 may extend into the substrate such that aportion of the passage extends through the bar and a parallel portion isembedded in the substrate, as shown in FIG. 5. Alternatively, thepassages 234 may be entirely embedded in the substrate such that thepassage extends below a bar and have the inlet and outlet at the bottomof the grooves on opposite sides of the bar.

The open passages 234 may be perpendicular to the longitudinal axis ofthe bar, or may be acute to the longitudinal axis. Moreover, the crosssectional area of the open passage may be constant along its length, ormay be tapered from the inlet to the outlet (or vice versa) to achieve adesired flow of steam and other fluids through the passage.

The refiner plate segment 200 may be formed by casting metal into a moldform of sand. An imprint of the refiner plate segment is formed in sandmolds which are clamped together to form a cavity that is substantiallythe same shape as the flinger plate. Metal is poured in the cavity ofthe sand mold to form the flinger plate. The open passages may be formedin the sand molds by three-dimensional printing all or a portion of thesand imprint for the refiner plate segment. Additionally, the openpassages may be made after the production of castings using drilling andmachining processes, or standard sand castings can have sand cores addedto create the open passages directly in the casting.

Except as otherwise expressly stated herein, the following rules ofinterpretation apply to this specification: (a) all words used hereinshall be construed to be of such gender or number (singular or plural)as to circumstances require; (b) the singular terms “a,” “an,” and“the,” as used in the specification and the appended claims includeplural references unless the context clearly dictates otherwise; (c) theantecedent term “about” applied to a recited range or value denotes anapproximation within the deviation in the range or values known orexpected in the art from the measurements; (d) the words “herein,”“hereby,” “hereto,” “hereinbefore,” and “hereinafter,” and words ofsimilar import, refer to this specification in its entirety and not toany particular paragraph, claim, or other subdivision, unless otherwisespecified; (e) descriptive headings are for convenience only and shallnot control or affect the meaning or construction of any part of thespecification; and (f) “or” and “any” are not exclusive and “include”and “including” are not limiting. Further, the terms, “comprising,”“having,” “including,” and “containing” are to be construed asopen-ended terms (i.e., meaning “including but not limited to”).

Recitation of ranges of values herein are merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range of within any sub ranges there between, unlessotherwise clearly indicated herein. Each separate value within a recitedrange is incorporated into the specification or claims as if eachseparate value were individually recited herein. Where a specific rangeof values is provided, it is understood that each intervening value, tothe tenth or less of the unit of the lower limit between the upper andlower limit of that range and any other stated or intervening value inthat stated range or sub range hereof, is included herein unless thecontext clearly dictates otherwise. All subranges are also included. Theupper and lower limits of these smaller ranges are also includedtherein, subject to any specifically and expressly excluded limit in thestated range.

The invention is:
 1. A mechanical refiner flinger plate comprising: afront face; a back face; a substrate separating the front face from theback face; a center hub extending from the front face; feeder barsextending from the front face, wherein the feeder bars extend radiallyoutward from the center; and a deep notch or hole disposed in a feederbar of the feeder bars, wherein the feeder bar has an area defining thedeep notch or hole, and the deep notch or hole extends through thefeeder bar and is configured to allow fluid to pass through the feederbar.
 2. The mechanical refiner flinger plate of claim 1, wherein thefeeding bar further comprises a leading side and a trailing sidedistally disposed from the leading side, wherein the deep notch or holefurther comprises a first end distally disposed from a second end, andwherein the first end is disposed radially outward from the second end.3. The mechanical refiner flinger plate of claim 1, wherein the deepnotch or hole includes multiple deep notches or holes disposed in thefeeder bar.
 4. The mechanical refiner flinger plate of claim 1, whereinthe deep notch or hole is disposed in each of the feeder bars.
 5. Themechanical refiner flinger plate of claim 1, wherein the deep notch orhole includes multiple deep notches and/or holes, at least one of whichis disposed in each of the feeder bars.
 6. The mechanical refinerflinger plate of claim 1, wherein the deep notch or hole furthercomprises a radially outermost edge at the first end of the deep notchor hole, wherein the radially outermost edge forms an obtuse anglebetween the adjacent notch or hole sidewall and the leading side of thefeeder bar.
 7. The mechanical refiner flinger plate of claim 1, whereinthe deep notch or hole further comprises a radially outermost edge atthe first end of the deep notch or hole, wherein the radially outermostedge is selected from a group consisting of a chamfer, a bevel, and acurve.
 8. The mechanical flinger plate of claim 1, wherein the notchextends through the feeding bar and partially into the substrate, or thehole is partially embedded in the substrate.
 9. A mechanical refinerplate segment comprising: a substrate having a radially inward edge anda radially outward edge; a refining surface including bars separated bygrooves wherein the bars and grooves extend towards the radially outwardedge; dams in the grooves, wherein the dams in each groove span betweenthe adjacent bars on opposite sides of the groove; and at least one openpassage extending through one of the adjacent bars, wherein the openpassage has one end adjacent a trailing side of one of the dams in thegroove.
 10. The mechanical refiner plate segment of claim 9, wherein theopen passage has a cross sectional area of at least nine (9) mm² for anentirety of a length of the open passage.
 11. The mechanical refinerplate of claim 9, wherein the open passage is separated from a ridge ofthe one of the adjacent bars by at least 10%, or 15%, or 25% of theheight of the one of the adjacent bars.
 12. The mechanical refiner platesegment of claim 9, wherein the bars and grooves extend from one sideedge of the substrate to an opposite side edge of the substrate.
 13. Themechanical refiner plate segment of claim 9, wherein there is one of theopen passages associated with at least 50% of the dams in the refinerplate segment.
 14. The mechanical refiner plate segment of claim 9,wherein the refiner plate segment is formed of a cast metal.
 15. Themechanical refiner plate segment of claim 9, wherein the refiner platesegment has a pie-shape and is configured to be arranged with additionalrefiner plate segments to form an annular refiner plate.
 16. Themechanical refiner plate segment of claim 9, wherein the refiner platesegment is a portion of an annular refiner plate.
 17. The mechanicalrefiner plate segment of claim 9, wherein the radially inward edge isconfigured to be adjacent an outer periphery of a flinger plate.
 18. Themechanical refiner plate segment of claim 9, wherein the at least oneopen passage is at least partially embedded in the substrate below theone of the adjacent bars.